python26 hw0.py mwe.txt mwehw0.txt
python26 hw1.py mwehw0.txt mwehw1.txt mwehw1_note.txt 
cp mwehw1.txt mwehw2.txt
python26 make_xml.py mwe.txt mwehw2.txt mwe.xml
xmllint --noout --valid mwe.xml
